I. We have developed a method based on machine vision to continuously measure kinematic parameters in third instar larvae during the first 4 hours of the dark cycle. This powerful approach enables the construction of behavioral profiles of individual larvae using high-throughput behavioral screening. We are measuring larvae from the Drosophila Genetic Reference Panel (DGRP). Preliminary results indicate that significant genetic variation among the lines is present for activity and rest measurements, which will enable us to identify candidate genes associated with these behaviors. II. We found that measures of rest and activity in Drosophila larvae have a genetic basis. We are currently associating these phenotypic measures with available whole-genome sequence data from the DGRP.